Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 11: Transport

HL 11.1: Vortrag

Montag, 22. März 2010, 14:00–14:15, H14

Quantized magnetic confinement in quantum wires — •Mihai Cerchez¹, Alexey Tarasov¹, Stefan Hugger¹, Hengyi Xu¹, Thomas Heinzel¹, Igor Zozoulenko², Urszula Gasser-Szerer³, Dirk Reuter⁴, and Andreas Wieck⁴ — ¹Heinrich-Heine-Universität, Düsseldorf, Germany — ²Linköping University, Norrköping, Sweden — ³ETH, Zürich, Switzerland — ⁴Ruhr-Universität Bochum, Germany

We report the experimental observation of magnetically bound electronic states in a quantum wire (QWR), built by AFM lithography in a GaAs/AlxGa1-xAs heterostructure with a two-dimensional electron gas (2DEG) at 45 nm below the surface. A strong, inhomogeneous magnetic field is produced in the central region of the wire under the edge of a Dy ferromagnetic film evaporated on top and magnetized along the wire. Electronic transport measurements on the QWR are performed as a function of a superimposed, homogeneous perpendicular magnetic field. When the homogeneous field is applied in the opposite direction to the field produced by the ferromagnetic film, such that the magnetic field changes sign twice inside the QWR, we observe resonances in the conductance, which we interpret as bound electronic states induced by the inhomogeneous diamagnetic shift of the wire modes. Supported by simulations using a recursive Green function technique, we identify in the LDOS two types of bound states, one bonding state (ring-like) associated to a maximum in the transmission probability and therefore in conductance, and an anti-bonding state associated to reflection resonances.